<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>复习</title>
    <style>
        .box{
            width: 200px;
            height: 200px;
            outline: 1px solid green;
            background-color: rgb(188, 238, 148);
        }
        .c{
            width: 100px;
            height: 100px;
            background-color: rgb(253, 208, 208);
            /* margin-top: 20px; */
        }
        .b1{
            margin-bottom: 50px;
            border-radius:50px 60px;
            border:1px solid red;
        }
        .b2{
            margin-top: 20px;
        }
    </style>
</head>
<body>
    <div class="box b1">b1</div>
    1
    <div class="box b2">
        b2
        <!-- <div class="c"></div> -->
    </div>
</body>
</html>